Molded insulation article



July 23, 1935. w. c. TREGONING 2,008,777

MOLDED INSULAT ION ARTICLE Filed May 7, 1931 UNITED STATES PATENT OFFICE MOLDED INSULATION ARTICLE William C. Tregoning, Vauwatosa, Wis., assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application May 7, 1931, Serial No. 535,608

9 Claims.

This invention relates molded insulation articles. The invention relates more particularly to improvements in lamp socket casings comprising separable insulating cap and body members of the character disclosed in my Patent No. 1,784,557, dated December 9, 1930.

An object of the invention is to provide an improved snap catch for releasably retaining the insulating cap and body members in assembled relation to each other.

Another object is to provide an insulating casing having an improved form of integral flexible tongue to greatly increase resistance to breakage of the latter in the event of a twisting strain upon the interlocked parts prior to release of the latch.

Another object is to provide insulating cap and body members having interlocking and latching elements of improved form.

Another and more specific object is to provide a simplified form of cap member adapted for production by a straight-line molding die.

Another object is to provide means whereby the cap and body members may be telescoped and then positively locked against separation by relative rotation thereof in either direction.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates certain embodiments of the invention which will now be described, it being understood that the embodiments illustrated are susceptible of modification without departing from the scope of the appended claims.

In the drawing, Figure 1 is a perspective view, in separated relation, of one form of cap and body members constructed in accordance with my invention.

Fig. 2 is a horizontal section, approximately on the line 22 of Fig. 1, with the cap and body members in telescoped engagement, but prior to relative rotation thereof to latch the same against separation.

Fig. 3 is a vertical sectional view of an alternative form of molded cap member which may be employed in conjunction with certain of the body members disclosed herein.

Fig. 4 is a fragmentary elevational view of a body member having a modified form of interlocking and latching projections.

Fig. 5 is a top plan view of the body member shown in Fig. 4,with a cap of the type illustrated in Fig. 1 shown in section after telescoping of the parts, but prior to relative rotation thereof to latching position.

to improvements in Fig. 6 is a fragmentary perspective view of a body member like that illustrated in Fig. 4, but modified to provide for conversion thereof from the keyless type to a type adapted to accommodate a key-type, pull-chain type of push-button type lamp socket.

Fig. '7 is a view similar to Fig. 4, but showing a slightly modified form of flexible tongue.

Fig. 8 is a fragmentary section, on the line 88 of Fig. '7, and

Fig. 9 is a fragmentary section on the line 99 of Fig. 4.

Referring first to Figs. 1 and 2, the numeral designates the molded insulating body member of a lamp socket casing and the numeral l6 designates the molded insulating cap member of such casing. The insulating material of which the body and cap member is formed is of substantially rigid but slightly flexible character, such, for instance, as the phenol-formaldehyde condensation product sold under the trade name of bakelite. As will be apparent, however, the cap member 16 could be formed of another type of insulating material.

As shown the body member 15 has formed integrally therewith six equally spaced circumferentially arranged projections H of substantially inverted L-shape. The relatively wide upper end portions of said projections are preferably located in a plane flush with the upper edge l8 of said body member, and the relatively narrow lower ends I! of said projections extend downwardly from the same (left-hand) side of each of said upper end portions.

The skirt portion 19 of cap member [6 is provided with a corresponding number of equally spaced grooves 20 which provide clearance for the projections l1 whereby said cap and body members may be telescopically engaged with each other in substantially any rotary relation thereof. It is ipreferred to form the cap member l6 by means of a simple straightline molding die, and accordingly by the molding operation the grooves 20 are preferably made to extend upwardly to the plane of the horizontal annular shoulder 2| shown in Fig. I. Thereafter the insulating material between the upper end portions of said grooves is ground out or milled by means of a suitable machine or tool to provide the annular groove 22 communicating with each of the grooves 20. It will of course be understood that the grooves 20 need not be made to extend so far upwardly by the molding operation, but the arrangement aforedescribed has the advantage of minimizing the amount of insulating material required to be ground or otherwise removed to form the annular groove 22. The cap member 16 may be of any suitable or desired external contour or configuration.

Extending downwardly for a suitable distance from the upper edge l8 of body member I5 is a non-radial slot 23 of the character disclosed in my patent aforementioned. In order to provide a flexible portion or tongue upon the body member IS, with certain important advantages over the arrangement disclosed in my patent aforementioned, I form in the body member a second slot or kerf 24 which extends from the slot 23 for a suitable distance circumferentially of member IS. The branch'slots 23 and 24 thus define a portion or tongue 25 which may be readily flexed inwardly with respect to the main portion of the wall of said body member l5,the overlapping edges of slot 23 cooperating to limit the degree of bending of said tongue.

Located upon tongue 25 adjacent to the free end thereof is an integral projection 26 which may be made relatively narrow as shown. When the relatively wide upper end portions of projections H are brought into register with grooves 20 in cap member l6 it will be seen that projection 26 is in a position between two of said grooves. Tongue 25 must therefore be bent inwardly to permit telescoping of the parts, and such bending may be effected by manually pressing upon the portion 26 of said projection 26. However, I prefer to provide at the upper end of projection 26 a bevel or cam surface 2t. whereby telescoping movement of the cap and body members will automatically effect inward bending of tongue 25.

The arrangement is such that the left-hand side 26 of projection 26 and the right-hand side N of the downward extension on the adjacent projection H, located to the right thereof, are spaced a predetermined distance apart,such distance being substantially equal to the width of the several grooves 20. Therefore, after telescoping of the cap and body members the same may be partially rotated in a clockwise direction with respect to each other to lock the same against endwise separation,such partial rotation being limited by engagement of the sides li with like side walls of the respective grooves 20. At the same time the projection 26 snaps into that groove 20 which has accommodated the lower end I1 of the projection I! to the right thereof and reverse rotation of the parts is positively prevented by engagement of side 26 of projection 26 with the opposite side wall of said groove 20. Such reverse rotation may, however, be effected to dis-assemble the parts by merely pressing inwardly or bending tongue 2 5.

While I have shown projection 26 as spaced or separated from the projection I! to the right thereof, it will be apparent to those skilled in the art that projection 26 may be widened toward the right to eliminate the space between the same and said projection |1.,such wider projection, of course, being provided with a beveled upper edge corresponding to 26 in Fig. 1.

The alternative form of molded insulating cap member l6 shown in Fig. 3 may be employed in lieu of the cap member l6 aforedescribed, without requiring any change in the structure of molded body member 15. Cap member i6 is substantially like the cap member disclosed in my patent aforementioned, except that the vertical and horizontal branches 2! and 28, respectively, of the several bayonet grooves are preferably of sub stantially equal depth. The cap member l6 requires the use of a somewhat complicated molding die for formation of the bayonet grooves, and I have found that a cap member of the character shown at H in Figs. 1 and 2 is equally satisfactory for my purpose. Cap member l6 further has the advantage that when employed with the other forms of body member now to be described the parts may be telescoped and then partially rotated in either direction relatively to each other to positively latch the same against separation.

It may be noted that I prefer to form the nonradial slot or branch slot 23 in body member l5 by the molding operation, whereas the slot or kerf 24 is formed or cut therein as by means of a rotating disc-saw, jig-saw, or the like.

The body member 29 in Fig. 4 is provided with slots or branch slots 23 and 24 identical with those aforedescribed. The equally spaced radial projections 30 in this case are of substantially rectangular contour, the same being of a width to telescope freely into the grooves 20 in cap l6 and having a height to fit snugly but slidably between the top and bottom walls of annular groove 22. The unequally spaced projection 3| is likewise located adjacent to the free end of tongue 25 formed by said slots 23 and 24, and said projection 3| is of a width to fit snugly between the side walls of any one of the several grooves 20 in cap I6. A beveled edge 3| is provided to facilitate telescoping of the cap and body members of the lamp socket casing, and a button or extension 3| is provided on said projection 3| -to facilitate bending of tongue 25 to release the parts for relative rotation and subsequent separation.

It will be noted that with the arrangement shown in Fig. 4 upon telescoping of the body member into cap member l6 these parts may be latched by merely rotating the same in either direction relatively to each other, until projection 3| snaps into one of the grooves 20. Projection 3| thereupon restrains the parts against relative rotation until the tongue 25 is bent inwardly to effect release of said projection from the walls of the cooperating groove in cap l6. As best shown in Fig. 5 the projection 3| is of less thickness at the side 3| thereof than at the opposite side 3| thereof to permit telescoping of the parts upon inward bending of tongue 25.

The body members of the casing thus far described have been shown as adapted to reception of lamp sockets of the keyless type. In Fig. 6 the body member 29 is in most respects identical with that shown in Figs. 4 and 5, and corresponding parts have been given like characters of reference. In Fig. 6, however, I have provided means whereby the body portion 29 of the casing may not only be employed in conjunction with lamp sockets of the keyless type, but the same may also be readily transformed to accommodate lamp sockets of the pull-chain type, key-type or pushbutton type. Thus as indicated the inner surface of the wall of member 29*- is provided, by the molding operation, with a recess or depression 32 of substantially the form shown. By providing an area having a relatively thin wall it is possible by means of a suitably shaped tool to out, remove or knock-out the thin wall portion 32 defined by recess 32, thus providing a notch to accommodate the handle of a key-socket or the guide-bell of a pull chain socket. In like manner recesses 33 and 34 are provided whereby the thin wall portions defined thereby may be readily removed to provide diametrically opposed notches of suitable size to accommodate the projecting portions of a socket of the push-button type.

The body member 29* illustrated in Figs. 7 and 8 is in most respects identical with that shown in Figs. 4' and 5, and like parts are designated by like characters of reference. In this form, however, the branch slot 24 instead of being cut inwardly in a plane at right angles to the outer surface of body member 29 as in the other figures, is cut in a plane angled upwardly with respect to said outer surface. This form of slot 20* has the advantage of forming overlapping walls whereby the portions of the lamp socket contained within the casing are normally concealed. Such overlapping of the walls of slot 24 has the further advantage of acting in the manner of slot 23 to limit inward bending of tongue 25.

As will be apparent the surrounding edge portions of the projections ll, 25 and 30, 3| preferably extend in planes at substantially right angles to the outer surface of the body members I5, 29, 29 and 29* respectively. The cap and body members may thus be readily assembled, and any tendency toward looseness or play therebetween when assembled is eliminated.

Moreover by providing a tongue 25 of the form illustrated it will be seen that after full assembly of the parts any twisting strain (either intentional or accidental) between the cap and body members will be very readily withstood without danger of breaking the tongue. This advantage is due to the fact that any such twisting strain is substantially normal to the entire width of the tongue at the junction thereof with the body member, and is not localized at any one point along the line of such junction.

The lamp socket (not shown) to be housed or enclosed by the cap and body members of the casing is formed in a suitable manner to permit the required degree of bending of the flexible tongue, as disclosed in my patent aforementioned. Also if desired any suitable or well known means may be provided to interlock the lamp socket and the body member of the casing against relative rotation. In the key, pull-chain and push-button types, however, the switch actuating elements of the lamp socket may be utilized to provide such an interlock with the body member.

Also as shown in Fig. 6 the projections 30 may be provided with rounded or beveled edges 30 to facilitate initial telescopic engagement of the cap and body members of the insulating casing.

What I claim as new and desire to secure by Letters Patent is:

1. In an electric lamp socket casing, in combination, a molded hollow body member of insulating material, said body member having a plurality of integral projections symmetrically arranged peripherally adjacent to the upper end thereof, said body member having a non-radial slot extending from the upper edge thereof and a second slot opening to said first-mentioned slot and extending at substantially a right angle with respect thereto, said slots defining a tongue which may be flexed along a line or region substantially parallel to said first-mentioned slot, and a locking projection carried by said tongue, said locking projection being unsymmetrically arranged with respect to said first-mentioned projections.

2. In an electric lamp socket casing, in combination, a molded hollow body member of flexible insulating material, said body member having a plurality of equally spaced radial projections adjacent to the upper end thereof, said body member having a vertical slot formed therein by the molding operation and a second slot extending in a direction at substantially a right angle to said first mentioned slot, the walls of said firstmentioned slot being non-radial with respect to the longitudinal center of said body member and the walls of said second-mentioned slot being angled upwardly with respect to the plane of the outer surface of said member, said slots defining a tongue which may be flexed inwardly with respect to the main portion of said body member and the overlapping walls of said slots jointly cooperating to limit the inward flexing of said tongue, and a latching projection formed integrally with said tongue adjacent to the free end thereof, said latching projection being unsymmetrically arranged with respect to said firstmentioned projections.

3. As an article of manufacture, a molded ho1- low insulating body member having an open upper end, said body member having an L-shaped slot formed therein to define a tongue, one branch of said slot opening to the upper end of said member, a plurality of projections formed integrally with said member and located adjacent to the upper end thereof and one of said projections being positioned adjacent to the free end of said tongue, 2. cap or cover for said body member, said cap having shouldered portions formed thereon to telescopically receive the upper end of said body member upon flexing of said tongue, said cap and body member being thereupon rotatable with respect to each other to lock the same against relative longitudinal movement, and said one of said projections being engageable with a shoulder formed on said cap to positively latch said parts against relative rotation.

4. An electric lamp socket casing comprising separately molded cap and body members of insulating material, one of said members having a flexible tongue formed integrally therewith and having its free and fixed ends spaced circumfercniially thereof, said members respectively having cooperating shoulders formed integrally therewith and arranged to restrain said members against endwise separation upon telescoping and subsequent partial relative rotation thereof in either direction, and an additional shouldered element carried by said tongue and adapted to positively but releasably engage other of said shoulders whereby said members are latched together upon such partial relative rotation thereof.

5. An electric lamp socket casing comprising independent cap and body members formed of substantially rigid but slightly flexible insulating material, and latching means for securing said members together in substantially any relative rotary position thereof and serving to hold the same together against endwise separation and relative rotary displacement, said latching means comprising shouldered insulating portions integral with the respective cap and body members and adapted for positive interlocking engagement with each other, a shouldered portion on one of said members being formed to require yielding movement thereof for effecting such interlocking engagement, the arrangement being such that said members may be joined by telescoping and subsequent partial relative rotation thereof in either direction.

6. As an article of manufacture, an electric lamp socket casing comprising separate cap and body members formed of substantially rigid but slightly flexible insulating material, said body member having a plurality of equally spaced projections of substantially inverted L-shape formed thereon adjacent to the upper edge thereof, said body member having a substantially L-shaped slot formed therein and opening to the upper edge thereof to provide a tongue, said body member having an additional projection unequally spaced from said first-mentioned projections and carried by said tongue, said cap member having a plurality of grooves extending from an edge thereof to accommodate said first-mentioned projections during telescoping of said cap and body members, said cap member also having an annular groove opening to said first-mentioned grooves to accommodate portions of said first-mentioned projections upon partial relative rotation of said parts, other portions of said projections acting to limit such relative rotation in one direction, and said additional projection thereupon acting to positively restrain said parts against relative rotation in the reverse direction.

'7. As an article of manufacture, an electric lamp socket casing comprising separately molded hollow cap and body members of insulating material, said cap member having a skirt portion provided in its inner surface with a multiplicity of equally spaced grooves and an annular groove communicating with each of said firstmentioned grooves, said grooves jointly defining spaced substantially rectangular projections, said body member having a multiplicity of equally spaced substantially inverted L-shaped projections formed thereon adjacent to the upper edge thereof, said rectangular projections and said inverted L-shaped projections cooperating to restrain said cap and body member against endwise displacement upon sequential telescoping and partial relative rotation thereof, and a flexible shouldered arm of insulating material formed integrally with said body member and cooperating with any one of said rectangular projections to positively but releasably retain said cap and body members in assembled relation to each other.

8. As an article of manufacture, an electric lamp socket casing comprising separately molded hollow cap and body members of insulating material, said cap member having a skirt portion provided in its inner surface with a multiplicity of equally spaced vertical grooves and an annular groove spaced upwardly from the lower edge of said skirt portion and communicating with each of said first-mentioned grooves, said vertical grooves and said annular groove serving jointly to provide a multiplicity of equally spaced substantially rectangular projections upon said inner surface of the skirt portion, said body member having a multiplicity of equally spaced projections of like shape formed exteriorly thereon adjacent to the upper edge thereof, the projections on said cap and body members cooperating with each other to restrain said members against endwise displacement upon sequential telescoping and partial relative rotation thereof, and flexible means formed integrally with said body member and including a latching element, said latching element having a pair of parallel shoulders formed thereon for cooperation jointly with the walls of any one of said vertical grooves to positively re- Lain said cap and body members in assembled ielation, said shouldered latching element being manually releasable to provide for dis-assembly of said cap and body members.

9. As an article of manufacture, an electric lamp socket casing comprising separately molded hollow cap and body members of insulating material, said cap member having a skirt portion provided in its inner surface with a multiplicity of equally spaced vertical grooves and an annular groove spaced upwardly from the lower edge of said skirt portion and communicating with each of said first-mentioned grooves, said vertical grooves and said annular groove serving jointly to provide a multiplicity of equally spaced substantially rectangular projections upon said inner surface of the skirt portion, said body member having a like number of equally spaced subctantially rectangular projections formed extcriorly thereon adjacent to the upper edge thereof, the projections on said body member cooperating with the vertical grooves in said cap memher to provide for telescopic engagement of said parts and said projections being rotatable in either direction within said annular groove to effect cooperative engagement thereof with the projections upon said cap member whereby the latter and said body member are restrained against endwise displacement relatively to each other, and means including a flexible element formed integrally with said body member, said flexible element having spaced vertical shoulders form-ed thereon and cooperable jointly with the walls of any one of said vertical grooves in said skirt portion to positively retain said cap and body members in assembled relation, said flexible element being readily releasable at will to provide for sequential rotary and telescopic movements of said cap and body members relatively to each other for dis-assembly thereof.

WILLIAM C. TREGONING. 

